Along with recent increases in data capacity, the importance of reliable and highspeed backup/restore techniques has been increasing. For example, in a backup utilizing a Volume Shadow copy Service (VSS), which is a general-purpose framework of Microsoft Corporation, when applications, backup software, and adapter software supporting VSS work together, a hot backup of data can be carried out without stopping online applications.
When performing a backup, a process in which a server mounts/unmounts volumes on a storage device occurs. In the technique described in below-described PTL 1, when a server is to unmount volumes, signatures of, for example, an MBR (Master Boot Record) and a PBS (Partition Boot Sector) are cleared, and the volumes are completely unmounted (for example, see FIG. 4 of the literature).